Hosting my own too. There's gmail as backup. But host my mail server, webmail, imap, smtp everthing.
Blocking spam isn't that problem. But making sure your mail goes to the receiver's inbox is.
You can block 90% of the spam by using only reverse DNS lookup -- doesn't match? Reject. 90% of the remaining can blocked using DKIM, SPF checks. No need for ip black hole check or spamassassin training.
The benefit : I can block a sender or his domain in a single click from webmail. Couldn't do that on gmail.
At the moment I don't filter on the server at all, because I think anyone should be able to reach me no matter how dumb the mail setup is. Send me mail by manually typing to a TCP:25 connection from a residential or mobile IP, I don't care. No DNS checks, etc. My postfix config is very permisive, only relaying is disabled.
I filter using bogofilter on emails delivered to my public addresses.
Private randomly generated aliases don't get filtered at all (only the sender knows them, so I just disable the address if it gets abused).
It works nicely, especially the private alias part.
I have alias/mailbox table in PostgreSQL DB, but don't bother with trying to connect postfix directly to the DB. I just dump the tables to the postmap files on each change. It's infinitely more performant and reliable, which is what this has to be.
I can also dump the DB to my MUA's config, and have it rewrite all the random addresses into something readable.
Blocking spam isn't that problem. But making sure your mail goes to the receiver's inbox is.
You can block 90% of the spam by using only reverse DNS lookup -- doesn't match? Reject. 90% of the remaining can blocked using DKIM, SPF checks. No need for ip black hole check or spamassassin training.
The benefit : I can block a sender or his domain in a single click from webmail. Couldn't do that on gmail.